The present invention relates to stabilized photographic amplified color developing compositions, sometimes known as xe2x80x9credoxxe2x80x9d amplification compositions, and to a method for their use. This invention also relates to two- and three-part kits that provide these compositions. This invention is useful in the field of photography to provide color photographic images.
The basic processes for obtaining useful color images from exposed color photographic silver halide materials include several steps of photochemical processing such as color development, silver bleaching, silver halide fixing and water washing or dye image stabilizing using appropriate photochemical compositions.
Photographic color developing compositions are used to process color photographic materials such as color photographic films and papers to provide the desired dye images early in the photoprocessing method. Such compositions generally contain color developing agents, for example 4-amino-3-methyl-N-(2-methane sulfonamidoethyl)aniline, as reducing agents to react with suitable color forming couplers to form the desired dyes. U.S. Pat. No. 4,892,804 (Vincent et al.) describes conventional color developing compositions that have been used with considerable commercial success in the photographic industry. Other known color developing compositions are described in U.S. Pat. No. 4,876,174 (Ishikawa et al.), U.S. Pat. No. 5,354,646 (Kobayashi et al.) and U.S. Pat. No. 5,660,974 (Marrese et al.).
Color development is generally followed with one or more desilvering steps, such as bleaching and fixing steps, or a combined bleach-fixing step. In such processes, color development can continue until the photographic material enters the bleaching or bleach-fixing solution.
Calcium or other metal ions in photographic processing compositions (such as color developing compositions) have been sequestered or complexed using a wide variety of organic complexing agents including various polyaminocarboxylic acids and polyphosphonic acids. Such innovations are described for example in U.S. Pat. No. 4,873,180 (Marchesano et al.), U.S. Pat. No. 6,416,940 (Haye et al.), and U.S. Pat. No. 6,159,670 (Buongiorne et al.).
In redox amplification (or RX) processes, imagewise exposed color photographic materials are developed to provide a silver image and then treated with a redox amplification composition (or a combined developer-amplifier composition) to form a dye image. Desilvering can then follow these steps. Such processes are well known in the art and described for example in U.S. Pat. No. 5,702,873 (Twist) and U.S. Pat. No. 5,723,268 (Fyson) and references cited therein.
A redox amplification composition (or as identified below as an amplified color developing composition) contains a reducing agent (usually a color developing agent) and a redox oxidizing agent (usually hydrogen peroxide) that is more powerful than silver halide and that will oxidize the reducing agent in the presence of the silver image that acts as a catalyst. The oxidized reducing agent (for example, the oxidized color developing agent) reacts with color forming couplers in the photographic material to form image dye. The redox amplification processes are particularly useful for processing color photographic papers that comprise relatively low amounts of silver chloride.
Since the amplified color developing compositions contain both an oxidizing agent and a reducing agent, they are inherently unstable and will decompose upon keeping. This instability is catalyzed during processing by various species in the processing environment that come from various sources.
U.S. Pat. 5,702,873 (noted above) describes the use of various metal ion sequestering agents such as polyaminocarboxylic, polyphosphonic or poly sulfonic acids that provide improved stability for various amplified color developing compositions.
Despite the continuing research by the industry to find ways to stabilize amplified color developing compositions, the industry has failed to provide sufficient stability so that such compositions could have general acceptance and use in commercial applications. Thus, there remains a need for means to increase the solution stability of redox amplification compositions. It is to this problem that the present invention is directed.
This invention provides an advance in the art with a stabilized photographic amplified color developing composition that comprises:
a) at least 0.001 mol/l of a color developing agent,
b) at least 0.005 mol/l of a redox oxidizing agent,
c) at least 0.001 mol/l of a hydroxylamine antioxidant, and
d) at least 0.0005 mol/l of a cyclicaminomethanediphosphonic acid or a salt thereof.
In preferred embodiments, the present provides an aqueous redox amplification composition having a pH of from about 10 to about 12 and comprising:
a) from about 0.001 to about 1 mol/l of a color developing agent that is 4-(N-ethyl-N-xcex2-hydroxyethylamino)-2-methylaniline sulfate (KODAK Color Developing Agent CD-4) or 4-(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methylphenylenediamine sesquisulfate (KODAK Color Developing Agent CD-3),
b) from about 0.001 to about 1 mol/l of hydroxylamine sulfate as an antioxidant for the color developing agent,
c) from about 0.005 to about 5 mol/l of hydrogen peroxide or a compound that provides hydrogen peroxide, and
d) from about 0.0005 to about 0.5 mol/l of morpholinomethanediphosphonic acid or a salt thereof.
This invention also provides a method for providing a color image comprising contacting an imagewise exposed color photographic element with a stabilized amplified color developing composition that comprises:
a) at least 0.001 mol/l of a color developing agent,
b) at least 0.005 mol/l of a redox oxidizing agent,
c) at least 0.001 mol/l of a hydroxylamine antioxidant, and
d) at least 0.0005 mol/l of a cyclicaminomethanediphosphonic acid or a salt thereof.
In preferred embodiments, it provides a method for providing a color image comprising contacting an imagewise exposed color photographic element with a stabilized photographic redox amplification composition that has a pH of from about 10 to about 12 and comprises:
a) from about 0.001 to about 1 mol/l of a color developing agent that is 4-(N-ethyl-N-xcex2-hydroxyethylamino)-2-methylaniline sulfate (KODAK Color Developing Agent CD-4) or 4-(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methylphenylenediamine sesquisulfate (KODAK Color Developing Agent CD-3),
b) from about 0.001 to about 1 mol/l of hydroxylamine sulfate as an antioxidant for the color developing agent,
c) from about 0.005 to about 5 mol/l of hydrogen peroxide or a compound that provides hydrogen peroxide, and
d) from about 0.0005 to about 0.5 mol/l of morpholinomethanediphosphonic acid or a salt thereof.
Still again, the present invention provides a method of photographic processing comprising the steps of:
A) contacting an imagewise exposed color photographic silver halide element with a stabilized amplified color developing composition that comprises:
a) at least 0.001 mol/l of a color developing agent,
b) at least 0.005 mol/l of a redox oxidizing agent,
c) at least 0.001 mol/l of a hydroxylamine antioxidant, and
d) at least 0.0005 mol/l of a cyclicaminomethanediphosphonic acid or a salt thereof, and
B) desilvering the color developed color photographic silver halide element.
A photographic processing kit of this invention comprises:
A) a first solution comprising a color developing agent, a cyclicaminomethanediphosphonic acid or salt thereof, and a hydroxylamine antioxidant, and
B) a second solution that comprises a redox oxidizing agent.
In other embodiments, a photographic processing kit comprises:
A) a first solution that comprises a color developing agent,
B) a second solution that comprises a cyclicaminomethanediphosphonic acid or salt thereof, and
C) a third solution that comprises a redox oxidizing agent, the first or second solution, or both, further comprising a hydroxylamine antioxidant.
The redox amplification composition of this invention offers a number of advantages over those currently known in the art. It is stabilized against loss in color developing agent activity, loss in antioxidant, and pH decrease with the use of a cyclicaminomethanediphosphonic acid (or salt thereof). In some embodiments, this stabilizing compound can be used in combination with one or more other polycarboxylic acids or polyphosphonic acids that are known in the art as metal ion sequestering agents.
The composition of this invention is generally formulated in aqueous form and can be in concentrated or diluted form.
The amplified color developing composition of this invention contains one or more reducing agents that are color developing agents generally in the form of a sulfate salt as a first essential component. More specifically, the useful color developing agents are well known in the art as those compounds that, in oxidized form, will react with dye forming color couplers in the processed materials. Such color developing agents include, but are not limited to, aminophenols, p-phenylenediamines (especially N,N-dialkyl-p-phenylenediamines) and others which are well known in the art, such as EP 0 434 097A1 (published Jun. 26, 1991) and EP 0 530 921A1 (published Mar. 10, 1993). It maybe useful for the color developing agents to have one or more water-solubilizing groups as are known in the art. Further details of such materials are provided in Research Disclosure, publication 38957, pages 592-639 (September 1996).
Preferred color developing agents include, but are not limited to, N,N-diethyl p-phenylenediamine sulfate (KODAK Color Developing Agent CD-2), 4-amino-3-methyl-N-(2-methane sulfonamidoethyl)aniline sulfate, 4-(N-ethyl-N-xcex2-hydroxyethylamino)-2-methylaniline sulfate (KODAK Color Developing Agent CD-4), p-hydroxyethylethylaminoaniline sulfate, 4-(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methylphenylenediamine sesquisulfate (KODAK Color Developing Agent CD-3), 4-(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methylphenylenediamine sesquisulfate, and others readily apparent to one skilled in the art. The most preferred color developing agent is KODAK Color Developing Agent CD-3 especially for photoprocessing of photographic color papers.
In order to protect the color developing agents from oxidation, one or more antioxidants are generally included in the amplified color developing compositions as a second essential component. Either inorganic or organic antioxidants can be used. Many classes of useful antioxidants are known, including but not limited to, sulfites (such as sodium sulfite, potassium sulfite, sodium bisulfite and potassium metabisulfite), hydroxylamine (and derivatives thereof), hydrazines, hydrazides, amino acids, ascorbic acid (and derivatives thereof), hydroxamic acids, aminoketones, mono- and polysaccharides, mono- and polyamines, quaternary ammonium salts, nitroxy radicals, alcohols, and oximes. Mixtures of compounds from the same or different classes of antioxidants can also be used if desired.
Especially useful antioxidants are hydroxylamine (such as hydroxylamine sulfate) and hydroxylamine derivatives as described for example, in U.S. Pat. No. 4,892,804 (Vincent et al.), U.S. Pat. No. 4,876,174 (Ishikawa et al.), U.S. Pat. No. 5,354,646 (Kobayashi et al.), U.S. Pat. No. 5,660,974 (Marrese et al.), and U.S. Pat. No. 5,646,327 (Bums et al.), the disclosures of which are all incorporated herein by reference with respect to antioxidants. Many of these antioxidants are mono- and dialkylhydroxylamines having one or more substituents on one or both alkyl groups. Particularly useful alkyl substituents include sulfo, carboxy, amino, sulfonamido, carbonamido, hydroxy and other solubilizing substituents. Hydroxylamine sulfate is a most preferred antioxidant.
Many of the noted antioxidants (organic or inorganic) are either commercially available or prepared using starting materials and procedures described in the references noted above in describing hydroxylamines.
As a third essential component, the amplified color developing compositions of this invention also include one or more redox oxidizing agents (also known as a redox oxidant) that include peroxy compounds such as hydrogen peroxide and compounds that provide hydrogen peroxide (for example addition compounds of hydrogen peroxide), sodium percarbonate, sodium perborate, sodium persulfate, butyl peroxide, and benzyl peroxide. Other redox oxidizing agents include cobalt (III) complexes including cobalt hexamine complexes, and periodates. Mixtures of one or several types of redox oxidizing agents can be used if desired.
Still another essential component of the color developing composition of this invention is that primary xe2x80x9cstabilizingxe2x80x9d compound that is a cyclicaminomethanediphosphonic acid (and salts thereof), or mixtures thereof, as described in U.S. Pat. No. 4,873,180 (noted above). xe2x80x9cCyclicaminoxe2x80x9d groups comprise 3- to 6-membered rings, including but not limited to substituted or unsubstituted aziridino, pyrrolidino, imidazolidino, piperidino, piperazino, isoindolino, and morpholino groups. The substituted or unsubstituted morpholino groups are preferred. Suitable substituents for the cyclicamino groups include, but are not limited to, alkyl groups having 1 to 4 carbon atoms, halo groups, nitro groups, cyano groups, aryl groups, alkoxy groups having 1 to 4 carbon atoms, aryloxy groups, sulfamoyl groups, acyloxy groups, acylamino groups, ureido groups, sulfonamido groups, hydroxy groups, and others that would be readily apparent to one skilled in the art from the teaching of U.S. Pat. No. 4,873,180, incorporated herein by reference.
The xe2x80x9ccyclicaminoxe2x80x9d groups are attached to a methyl group that includes two phosphonic acids (or alkali metal or ammonium salts thereof) and the remaining valence of the methyl group can be hydrogen, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.
Representative cyclicaminomethanediphosphonic acids (or salts thereof) are compounds 7-17 of U.S. Pat. No. 4,873,180 (noted above). A most preferred compound of this type is morpholinomethanediphosphonic acid or a salt thereof that is commercially available as BUDEX(trademark) 5103 from Budenheim (Germany).
Buffering agents are generally present in the amplified color developing compositions of this invention to provide or maintain desired alkaline pH of from about 8 to about 13, and preferably from about 10 to about 12. Useful buffering agents include, but are not limited to carbonates, borates, tetraborates, glycine salts, triethanolamine, diethanolamine, phosphates and hydroxybenzoates. Alkali metal carbonates (such as sodium carbonate, sodium bicarbonate and potassium carbonate) are preferred buffering agents. Mixtures of buffering agents can be used if desired.
In addition to buffering agents, pH can also be raised or lowered to a desired value using one or more acids or bases. It may be particularly desirable to raise the pH by adding a base, such as a hydroxide (for example, sodium hydroxide or potassium hydroxide).
Another optional component of the amplified color developing composition of this invention is a metal ion sequestering agent other than the cyclicaminomethanediphosphonic acids noted above. Such compounds include, but are not limited to aminopolycarboxylic acids (and salts thereof) and aminopolyphosphonic acids (and salts thereof) that have at least two (and preferably five) phosphonic acid (or salt) groups. A mixture of such compounds can be used if desired. Suitable salts include ammonium and alkali metal ions salts. Useful amounts of such metal ion sequestering agents are well known in the art and are generally at least 0.0025 mol/l.
Aminopolycarboxylic acids include the various compounds commonly used as ligands in photographic bleaching agents for example as described in U.S. Pat. No. 4,546,068 (Kuse), U.S. Pat. No. 4,596,765 (Kurematsu et al.), U.S. Pat. No. 4,892,804 (noted above), U.S. Pat. No. 4,975,357 (Buongiorne et al.), U.S. Pat. No. 5,034,308 (Abe et al.), and Research Disclosure publications Item 20405 (April, 1981), Item 18837 (December, 1979), Item 18826 (December, 1979), and Item 13410 (December, 1975).
Examples of such compounds include, but are not limited to, ethylenediaminetetraacetic acid (EDTA), 1,3-propylenediaminetetraacetic acid (PDTA), diethylenetriaminepentaacetic acid (DTPA), cyclohexanediamine-tetraacetic acid (CDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), ethylenediaminedisuccinic acid (EDDS) as described in U.S. Pat. No. 5,679,501 (Seki et al.) and EP 0 532 001B1 (Kuse et al.). Other useful disuccinic acids are described in U.S. Pat. No. 5,691,120 (Wilson et al.). Aminomonosuccinic acids (or salts thereof) have at least one nitrogen atom to which a succinic acid (or salt) group is attached, polyamino monosuccinic acids, ethylenediamine monosuccinic acid (EDMS).
Other classes of aminopolycarboxylic acids or polyaminopolycarboxylic acids include iminodiacetic acid and its derivatives (or salts thereof), including alkyliminodiacetic acids that have a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms (such as methyl, ethyl, n-propyl, isopropyl, and t-butyl) as described in EP 0 532 003A1 (Kuse et al.). Particularly useful alkyliminodiacetic acids are methyliminodiacetic acid (MIDA) and ethyliminodiacetic acid (EIDA).
Still other useful aminopolycarboxylic acids can be represented by the following Structure I: 
wherein p and q are independently 1, 2 and 3, and preferably each is 1. The linking group X can be H, with no carboxy group attached, or it may be any divalent group that does not bind ferric ion and does not cause the resulting ligand to be water-insoluble. Preferably, X is a substituted or unsubstituted alkylene group, substituted or unsubstituted arylene group, substituted or unsubstituted arylenealkylene group, or substituted or unsubstituted alkylenearylene group.
Still other useful aminocarboxylic acids include but are not limited to, xcex2-alaninediacetic acid (ADA), nitrilotriacetic acid (NTA), glycinesuccinic acid (GSA), 2-pyridylmethyliminodiacetic acid (PMIDA), citric acid, tartaric acid, 1,3-diamino-2-propanetetraacetic acid (DPTA), diethylenetriaminepentaacetic acid (DTPA), and iminodisuccinic acid, and salts thereof.
Particularly useful additional aminopolyphosphonic acids include compounds represented by the following Structure II: 
wherein L, Lxe2x80x2, L1, L2, L3, L4 and L5 are independently substituted or unsubstituted divalent aliphatic linking groups, each independently having 1 to 4 carbon, oxygen, sulfur or nitrogen atoms in the linking group chain. Preferably, these substituted or unsubstituted divalent linking groups have 1 to 4 carbon atoms in the linking group chain (such as substituted or unsubstituted branched or linear alkylene groups). More preferably, the divalent linking groups are independently substituted or unsubstituted methylene or ethylene. Most preferably, L and Lxe2x80x2 are each substituted or unsubstituted ethylene (preferably unsubstituted), and each of the other linking groups is an unsubstituted methylene group. M is hydrogen or a monovalent cation (such as ammonium ion or an alkali metal salt).
The noted divalent groups can be substituted with any substituent that does not interfere with the desired performance of the sequestering agent, or with the photochemical properties of the color developing compositions. Such substituents include, but are not limited to, hydroxy, sulfo, carboxy, halo, lower alkoxy (1 to 3 carbon atoms) or amino.
A particularly useful compound of this type is diethylenetriaminepentamethylenephosphonic acid or an alkali metal salt thereof (available as DEQUEST(trademark) 2066 from Solutia Co.).
The amplified color developing compositions of this invention can also include one or more of a variety of other addenda that are commonly used in photographic processing compositions, including alkali metal halides (such as potassium chloride, potassium bromide, sodium bromide and sodium iodide), auxiliary co-developing agents (such as phenidone type compounds particularly for black and white developing compositions), antifoggants, development accelerators, optical brighteners (such as triazinylstilbene compounds), wetting agents, fragrances, stain reducing agents, surfactants, defoaming agents, and water-soluble or water-dispersible color couplers, as would be readily understood by one skilled in the art (see for example, Research Disclosure publication 38957 noted above). The amounts of such optional additives are well known in the art also.
The following TABLE I lists the general and preferred amounts of the essential and some optional components of the amplified color developing compositions of this invention. The preferred ranges are listed in parentheses ( ), and all of the ranges are considered to be approximate or xe2x80x9caboutxe2x80x9d in the upper and lower end points. During processing, the actual concentrations can vary depending upon extracted chemicals in the composition, replenishment rates, water losses due to evaporation and carryover from any preceding processing bath and carryover to the next processing bath. The amounts are total concentrations for the various components that can be present in mixtures.
The amplified color developing compositions of this invention have utility to provide color dye image in imagewise exposed color photographic silver halide elements comprising a support and one or more silver halide emulsion layers containing an imagewise distribution of developable silver halide emulsion grains and dye providing chemistry. A wide variety of photographic elements (both color negative and color reversal films and papers, and color motion picture films and prints) containing various types of emulsions can be processed using the present invention, the types of elements being well known in the art (see Research Disclosure publication 38957 noted above). In particular, the invention can be used to process color photographic papers of all types of emulsions including so-called xe2x80x9chigh chloridexe2x80x9d and xe2x80x9clow chloridexe2x80x9d type emulsions, and so-called tabular grain emulsions as well.
The present invention is particularly useful to process high chloride (greater than 70 mole % chloride and preferably greater than 90 mole % chloride, based on total silver) emulsions in photographic color papers. Such materials can have any useful amount of silver coated in the one or more emulsions layers, and in some embodiments, low silver (that is, less than about 0.8 g silver/m2) elements are processed with the present invention. The layers of the photographic elements can have any useful binder material or vehicle as it known in the art, including various gelatins and other colloidal materials.
Representative commercial color papers that are useful in the practice of this invention include, but are not limited to, KODAK EKTACOLOR EDGE V, VII and VIII Color Papers (Eastman Kodak Company), KODAK ROYAL VII Color Papers (Eastman Kodak Company), KODAK PORTRA III, IIIM Color Papers (Eastman Kodak Company), KODAK SUPRA III and IIIM Color Papers (Eastman Kodak Company), KODAK ULTRA III Color Papers (Eastman Kodak Company), FUJI SUPER Color Papers (Fuji Photo Co., FA5, FA7 and FA9), FUJI CRYSTAL ARCHIVE and Type C Color Papers (Fuji Photo Co.), KONICA COLOR QA Color Papers (Konica, Type QA6E and QA7), and AGFA TYPE II and PRESTIGE Color Papers (AGFA). The compositions and constructions of such commercial color photographic elements would be readily determined by one skilled in the art.
KODAK DURATRANS, KODAK DURACLEAR, KODAK EKTAMAX RAL and KODAK DURAFLEX photographic materials and KODAK Digital Paper Type 2976 can also be processed using the present invention. The compositions and constructions of such commercial color photographic elements can be readily determined by one skilled in the art.
Processed of an imagewise exposed photographic silver halide element is generally carried out by contacting the element with the amplified color developing composition of this invention under suitable time and temperature conditions, in suitable processing equipment, to produce the desired developed color dye image. Additional processing steps can then be carried out using conventional procedures, including but not limited to, one or more bleaching, fixing, bleach/fixing, washing (or rinsing), stabilizing and drying steps, in any particular desired order as would be known in the art. An intermediate xe2x80x9cstopxe2x80x9d bath can be used between the amplified color development step and a bleaching step. Useful processing steps, conditions and materials useful therefor are well known for the various processing protocols as described for example in U.S. Pat. No. 5,723,268 (noted above).
The photographic elements processed in the practice of this invention can be single or multilayer color elements. Multilayer color elements typically contain dye image-forming units sensitive to each of the three primary regions of the visible spectrum. Each unit can be comprised of a single emulsion layer or multiple emulsion layers sensitive to a given region of the spectrum. The layers of the element can be arranged in any of the various orders known in the art. In an alternative format, the emulsions sensitive to each of the three primary regions of the spectrum can be disposed as a single segmented layer. The elements can also contain other conventional layers such as filter layers, interlayers, subbing layers, overcoats and other layers readily apparent to one skilled in the art. A magnetic backing can be included on the backside of conventional supports.
More details of the element structure and components, and suitable methods of processing various types of elements are described in Research Disclosure publication 38957 noted above. Included within such teachings in the art is the use of various classes of cyan, yellow and magenta color couplers that can be used with the present invention (including pyrazolone and pyrazolotriazole type magenta dye forming couplers). Preferably, the present invention can be used to process color photographic papers having pigmented resin-coated paper supports.
Processing according to the present invention can be carried out using conventional deep tanks holding processing solutions. Alternatively, it can be carried out using what is known in the art as xe2x80x9clow volume thin tankxe2x80x9d processing systems, or LVTT, which have either a rack and tank or automatic tray design. These processors are sometimes included in what are known as xe2x80x9cminilabs.xe2x80x9d Such processing methods and equipment are described, for example, in U.S. Pat. No. 5,436,118 (Carli et al) and publications noted therein.
Amplified color development is generally followed by desilvering using separate bleaching and fixing steps, or a combined bleach/fixing step using suitable silver bleaching and fixing agents. Numerous bleaching agents are known in the art, including hydrogen peroxide and other peracid compounds, persulfates, periodates and ferric ion salts or complexes with polycarboxylic acid chelating ligands. Particularly useful chelating ligands include conventional polyaminopolycarboxylic acids including ethylenediaminetetraacetic acid and others described in Research Disclosure publication 38957 noted above, U.S. Pat. No. 5,582,958 (Buchanan et al.) and U.S. Pat. No. 5,753,423 (Buongiorne et al.). Biodegradable chelating ligands are also desirable because the impact on the environment is reduced. Useful biodegradable chelating ligands include, but are not limited to, iminodiacetic acid or an alkyliminodiacetic acid (such as methyliminodiacetic acid), ethylenediaminedisuccinic acid and similar compounds as described in EP 0 532,003A1, and ethylenediamine monosuccinic acid and similar compounds as described in U.S. Pat. No. 5,691,120 (Wilson et al.). Useful fixing agents are also well known in the art and include various thiosulfates and thiocyanates or mixtures thereof.
The processing time and temperature used for each processing step of the present invention are generally those conventionally used in the art. For example, redox amplification is generally carried out at a temperature of from about 20 to about 50xc2x0 C. The overall processing time can be up to 4 minutes, and preferably from about 90 to about 180 seconds. Shorter overall color development times, for example from about 15 to about 30 seconds, are desired for processing color photographic papers in the practice of this invention.
The amplified color developing composition of this invention can be used as a working strength solution or replenisher.
Generally, the amplified composition of this invention is formulated by mixing two or three xe2x80x9cpartsxe2x80x9d of individual solutions that are manufactured, transported, and stored separately or as amplified color developing xe2x80x9ckitsxe2x80x9d prior to use. Thus, an amplified color developing kit of this invention can include a first xe2x80x9cpartxe2x80x9d or solution that includes all of the essential components (color developing agent, hydroxylamine antioxidant, and cyclicaminomethanediphosphonic acid) except the redox oxidizing agent (such as a peroxide) that is included in a second xe2x80x9cpartxe2x80x9d or solution.
Alternatively, the amplified color developing kit of this invention includes three parts that have, as a minimum, the following components:
Part A: Color developing agent,
Part B: Cyclicaminomethanediphosphonic acid (or salt thereof), and
Part C: Redox oxidizing agent.
A hydroxylamine antioxidant can be included in either Part A or Part B in the three-part kit. Various optional components can be included in any or all of these parts. The amounts of the essential and optional components in the various parts would be readily known in the art.
The color images obtained using the present invention can be further processed electronically through conventional digital means, transmitted, modified, or stored in digital or physical form.
The following examples are provided to illustrate the practice of this invention and not to limit it in any way. Unless otherwise indicated, percentages are by weight.